Dealing with Data Corruption
Incorrect document contents, missing information, gobbledegook, application crashes or hangs when opening documents, inconsistent results when copying files, inordinately slow file operations, a sudden and unexplained full hard disk, missing files or folders, lost or changed permissions on files, unable to logon, and many other weird goings on can be symptomatic of corruption.
Professional data recovery specialists charge anywhere from $US250 to $US2,000 or more to try to recover lost data from disks and CDs, yet there is no guarantee you will get anything back. This article provides some resources that you can try in order to recover your lost or corrupt data, either on hard disk, CD or DVD.
Unless you are experienced at troubleshooting corruption issues, you should read through all of these articles before deciding on a course of action.
If you need information on how to make backups to deal with future lost files or corruption, read the article on this site titled Solutions for Backup and Recovery.
The Golden Rule
If the data on your hard disk is in trouble, DO NOT use the machine. Simply booting an OS causes data to be written to disk. If you are trying to recover deleted files, the space that they used to occupy can be over-written. If your disk is corrupt, writing data to the disk can make it much worse than it already is.
Disk Error Checking
The Microsoft knowledge base article, How to Perform Disk Error Checking in Windows XP, describes how to check the integrity of the hard disk drive in Windows XP.
Alternative: At a command prompt, type the following command, and then press ENTER: chkdsk volume_label: /v /f
If you want to know more about what chkdsk does, read the in-depth KB article, An Explanation of the New /C and /I Switches That Are Available to Use with Chkdsk.exe.
The How to Locate and Correct Disk Space Problems on NTFS Volumes in Windows XP article describes how to check NTFS disk space allocation to either discover offending files and folders or locate volume corruption.
Recovery
Console and System File Checker
If you cannot start your computer in safe mode or by using the Last Known Good Configuration startup option, you can use Recovery Console. With the appropriate permissions, you can use this command-line interface to start recovery tools, start and stop services, access files on hard disks, and perform advanced tasks, such as manually replacing corrupted system files. You can run Recovery Console from the Windows XP Professional operating system CD, or you can install it as a startup option. A complete list of Recovery Commands is available here. Other related articles include Install the Recovery Console as a startup option, Start the computer and use the Recovery Console , Recovery Console overview, and Startup options .
System File Checker gives an administrator the ability to scan all protected files to verify their versions. If System File Checker discovers that a protected file has been overwritten, it retrieves the correct version of the file from the cache folder or the Windows installation source files, and then replaces the incorrect file. System File Checker is the main component of the Windows File Protection Feature .
Disaster Recovery Tools
Read Microsoft Technet's Disaster Recovery Tools article. From the website: Software and hardware issues can affect the way that your system functions. Severe problems might prevent you from starting Windows XP Professional normally. Installing incompatible software, incorrectly changing system configuration settings, or installing faulty device drivers can cause system instability or a Stop error. Hardware that is defective, malfunctioning, incorrectly installed, or incorrectly configured can also cause instability or a Stop error. Deleted or corrupted system files caused by problems such as user error or virus activity can cause data loss or prevent you from starting the operating system.
Disk and Maintenance Tools is another excellent Technet resource. Windows XP Professional provides disk and maintenance tools you can use to prevent problems from occurring. Some of the most useful tools are listed here. The disk-related tools allow you to view disk information and correct a problem before it becomes a serious issue.
Technet also has an article about System File Tools to help you troubleshoot problems caused by incompatible, missing, or corrupted driver and system files. Helpful tools for troubleshooting system and driver file issues are listed. These tools enable you to detect and correct issues caused by problem files, or prevent their installation.
Troubleshooting Disks and File Systems. Hard disk and file system errors can result from a variety of problems, such as hardware failures, power outages, poor system maintenance, viruses, and human error. When you are troubleshooting problems related to disks and file systems, you can refer to this chapter for information about troubleshooting tools, volume and disk error conditions, viruses, and stop messages. You can also use this chapter to obtain detailed descriptions of the master boot record (MBR), the GUID partition table (GPT), and the boot sectors.
Restoring the MBR. You must repair the MBR if it becomes corrupted and you can no longer access any volumes on that disk. You can use several tools to repair the MBR. Which tool you choose depends on whether the partition table is also damaged and whether you can start Windows XP Professional.
Replacing the Boot Sector. If Ntldr is damaged or missing, or if the boot sector is corrupted, you can resolve either problem by using the Recovery Console.
DiskProbe is a sector editor tool for Windows XP Professional that allows users who are members of the Administrators group to directly edit, save, and copy data on a physical hard disk. With careful use of DiskProbe, you can replace the master boot record (MBR), repair damaged partition table information, and repair or replace damaged boot sectors or other file system data. You can also use DiskProbe to save MBRs and boot sectors as backup binary files in case the original sectors become damaged by viruses, human error, hardware problems, power outages, or similar events.
Automated System Recovery is a last resort option to use after you have unsuccessfully tried other recovery methods, such as rolling back drivers, restoring from backups, performing parallel installations, and using System Restore. ASR restores system state files and settings, and restores your ability to start your system. For example, hard disk corruption might prevent you from starting Windows XP Professional, and the damage might be serious enough to prevent you from using safe mode, Recovery Console, or the Last Known Good Configuration. ASR automates the process of backing up and restoring system state information and files that are needed on the system volume to start Windows XP Professional.
Other Resources
The following links are not recommendations or endorsements. You must make your own mind up about what tool is appropriate for your situation. The feature lists were obtained from the respective websites.
Winternals Disk Commander: Features; Salvages data from unbootable systems. Scans entire disk for lost or corrupt volumes. Allows recovered files to be copied to a working drive. Restores volumes and replaces the MBR. Compatible with Windows XP/2000/Me/NT4/9x and with Remote Recover. Runs from Win32, a DOS boot diskette, Windows XP/2000/NT setup-style diskettes, or from a bootable CD-ROM.
FILERECOVERY® for Windows® 3.0: Features; Recovery of deleted files (plus full NTFS recovery support including encrypted and compressed files! Competition products cannot recover encrypted files.) Recovers files with the original time and date stamp. Supports the saving of recovered files on network drives.
Ontrack EasyRecovery: Features; Ontrack EasyRecovery™ offers easy to use, do-it-yourself software solutions to recover, repair, and restore your valuable data. Comprised of proprietary data recovery and repair tools, EasyRecovery software is based on our 17 years of experience performing more than 125,000 data recoveries. Trust your data to Ontrack, the worldwide leader in data recovery.
Restorer2000: Features; Restorer2000's powerful algorithms can undelete and recover files with foreign-language filenames, long filenames, NTFS-compressed filenames, deleted files, alternative data streams such as Windows 2000 / XP file information and files from corrupted or formatted hard drives in a matter of few seconds.
R-Studio: Features; A family of data recovery and undelete utilities. Empowered by new unique data recovery technologies, it is the most comprehensive data recovery solution for FAT12/16/32, NTFS, NTFS5, and Ext2FS. It recovers data both on local logical and physical disks, as well as disks on remote computers over networks, even if their partition structures are damaged or deleted. RAID reconstruction and Dynamic disk support are included, as well as support for recovering encrypted files, compressed files, and alternative data streams. File/disk content can be viewed and edited in the hexadecimal editor. Flexible parameter settings give you absolute control over data recovering.
DFSee: Features; As an analysis and recovery tool for most used file systems. This includes boot-sectors, superblocks and low-level directory structures. For most supported file systems some specific commands are available that fix common problems with that file system. To support a large number of possible file systems, DFSee uses specific modes of operation. Every mode has its own set of dedicated commands and recognized data formats (sector types). Generic commands (and sector types) are available in all modes. On selecting a data-source (disk, partition, volume) DFSee will try to recognize the involved file system and activate support for it automatically.
IsoBuster: Features; Data recovery from CD and DVD. Better Error handling and several retry-mechanisms to aid you in getting the data anyway. The use of alternative ways to get to the data, get the best out of your CD/DVD-ROM drive. CDs stay 'readable' after problems (such as Buffer Under-run). Read and Extraction of files, CD/DVD images, tracks and sessions from all optical media. Supports: CD-i, VCD, SVCD, CD-ROM, CD-ROM XA, CD-R, CD-RW, DVD-ROM, DVCD, DVD-RAM, DVD-R, DVD-RW, DVD+R, DVD+RW, Mpg (*.dat) Extraction and dat2mpg 'in one'...
Revision Date: 29 Nov 2003